Season pork with salt and pepper. Chop the fresh thyme and rub on pork. Add olive oil to an iron skillet and sear all sides of the pork. In a crockpot, add bay leaves, onions, carot, celery, milk, and chicken stock. Set to high. Add pork to crockpot and cover. Cook oh high for 4-6 hours.
Remove pork carefully, as not to break apart. Put in an oven proof dish and broil just long enough to crisp outside. Using a wand, or blender, blend remaining liquid from the crockpot while slowly adding flour by the tablespoon to thicken. Remove pork from oven and serve with gravy. This dish goes well with mashed potatoes.